Given how easy it can be to get discouraged about progress in addressing climate change, I think it’s helpful periodically to remember how much progress the U.S. has made in fighting air pollution.  It thus seemed useful to note this story about current conditions in New Delhi, where PM levels are so high that one million (!) students are being kept home from school.

It’s also helpful to remember the tension inherent in the climate change fight.  One of the biggest obstacles to progress is the desire of developing countries to raise their standards of living with cheap energy.  At the same time, developed countries find it easier to incur the short-term costs required to attack air pollution aggressively.  Threading that needle remains one of the most difficult problems in mitigating climate change.